Facts:

Principles:

Eating would be pretty boring if we didn’t have
taste buds! Everything would taste the same.

Most insects use their mouths to taste flavors just as we
do. But some insects can use other parts of their bodies to
taste with, too! For example, a butterfly tastes food with
its mouth and its feet. Ants can taste food with their mouths
and with their antennae.

People can only taste food and liquids with the taste buds
in their mouths. But we sense flavors by using our sense of
smell, too!

We also have a few taste buds on the lips (especially
salt-sensitive ones), the inside of the cheeks, the underside
of the tongue, the roof of the mouth, and the back of the
throat.

Materials:

Room Preparation

Safety Precautions

Be careful not to get the food items in your eyes. If you do,
rinse out thoroughly with cold water.

Procedures and Activity

Introduction

Ask the guiding questions:

What are taste buds?

First, talk about taste.
Share information about different foods and liquids that are
sweet, salty, sour, and bitter. You might write down these
categories on a blackboard or piece of paper and jot down
their examples.

Why don’t all foods and liquids taste the same?
Wouldn’t it be boring if everything did taste the
same?

Introduce concept of little organs on our tongues called
taste buds and how these sense and communicate to us
different flavors.

Where are the buds for particular tastes
located?

Our experimentation will show that taste buds are not
evenly distributed over the tongue. Certain tastes are
experienced more intensely in some areas than others.

Today, we are doing an experiment to help us figure out
where our different taste buds are located on our tongues.

Activity

Look at the handout and talk about the shape of our
tongues. Take time to think about how we are going to
describe where we taste different flavors—tip of
tongue, back of tongue, sides or edges of tongues. On the
sides or edges, we can break it down to more towards the
front or more towards the back of the tongue.

Use a toothpick to apply lemon juice to the tip, back
and sides of the tongue. Think about what area of the tongue
responds to the sour flavor of the lemon juice. Put a check
in the box on the chart on the handout where you think you
sensed the sour flavor of the lemon juice.

For powdered materials, you may need to lick your toothpick
before you dip it into a cup to get a sample. Dip the
toothpick into the powdered coffee and experiment with dabbing
it on your tongue in different locations. Where do you pick
up the bitter flavor of coffee? Put a check in the box on
the chart where you sensed the coffee’s bitter
flavo.

Dip the toothpick into sugar. Again, experiment with
dabbing sugar on different locations of your tongue. Where do
you pick up a sweet flavor? Put a check on the box on your
chart.

Dip toothpick into salt (you may need to lick the toothpick
first!) Try dabbing salt on your tongue. Where do you really
pick up a salty flavor and taste? Check the box on your
chart.

Closing - Original Question

Ask again,

1. What are taste buds?

2. Where are our taste buds located on our tongues?

Share the information they gathered from doing their
experiments. On what part of the tongue did we sense salty,
sweet, bitter, and sour flavors?

Evaluation

Let them share their information about taste buds with someone
else. Encourage them to help others repeat the experiment.

During discussions, listen for evidence that they understand
we sense flavors due to taste buds located on our tongues and
that taste buds are located in special areas of the
tongue.

Extension Ideas

Repeat the experiment, but this time plug your nose! You will
find that our noses help us detect flavors.

Pick out an insect or other animal to research and study. How
does it detect flavors in foods and liquids? Ants and
butterflies are fun to learn about.

Find further information at these sites:

That’s
Tasty from U. Washington’s Neuroscience for Kids
site also has links to other, more technical info about taste.

Careers Related to Lesson Topic

Prerequisite Vocabulary

Little organs found on the tongue that sense and communicate different
flavors in foods and liquids. The main types of flavors and sensations
are sweet, salty, bitter, and sour.

Why is there no “Answer Key”?

Such maps of our tongues do exist, but we choose not to provide one. First, there is too much individual variation (and variation over the course of your life, as you lose taste buds) for a single, accurate answer key. But primarily, we choose not to provide the “right answers” because that would undermine the purpose of these activities, which is to communicate not so much specific knowledge as the process of doing science: observing carefully, forming hypotheses, and drawing conclusions based upon your own experimental data. A good scientist does not waste time asking questions that she already knows the answers to, and she tries mightily to avoid interpreting her data to fit a foregone conclusion.